Water-heating attachment for hot-air furnaces



Nov. 15, 1927. 1,649,660

c. J. BRISTOL WATER HEATING ATTACHMENT FOR HOT AIR FURNACES Filed Dec. 21. 1926 Patented Nov. 15, 1927.

' UNITED STATES PATENT OFFICE.

CYRUS J. BRISTOL, OF DES MOINES, IOWA, ASSIGNOR T GLOBE MACHINERY 6'2; SUPPLY COMPANY, OF DES MOINES, IOWA, A CORPORATION OF IOWA.

WATER-HEATING ATTACHMENT FOR HOT-AIR FURNACES.

Application filed December 21, 1926. Serial No. 156,121.

The object of my invention is to provide a water heating attachment of simple, durable and inexpensive construction, formed of a single piece of ordinary iron pipe and so shaped that it may be readily, quickly and easily installed in the hot air furnaces now in common use, without alteration of the furnace, and when installed will form an cilicient water heater so constructed and arranged as to be free from so-called steam pockets which tend to create vibrations or poundings in the water heating system.

My invention consists in the construction of the heating unit of a single piece of ordi nary iron pipe, and so shaped as to attain the objects contemplated, as hereinafter more fully set forth, pointed out in my claim, and illustrated in the accompanying drawings, in which:

Figure 1 shows a side elevation of the water heating unit.

Figure 2 shows a top or plan view of the same installed in a portion of a furnace wall which is shown in section; and

Figure 3 shows an end elevation of the water heating unit.

Referring to the accompanying drawings, it will be seen that the entire unit is formed complete of a single length of pipe, and one 30 of the desirable features of my invention is that ordinary iron pipe of the kind commonly employed by plumbers for similar pur poses may be readily and easily bent to the shape disclosed in the drawings by means of the ordinary apparatus in common use, such for instance as the well known pipe bending press and suitable dies or formers.

The pipe, when formed, comprises esseutially an upper and a lower member. The upper member is indicated by the numeral 10, and, as will be seen in the drawings, is straight and provided at its outer end with a screw thread 11. The lower member is provided with a corresponding screw thread and is parallel with the member 10 at a point adjacent to the screw thread portion 12. This parallel portion is indicated by the numeral 13.

In this connection it should be explained that the hot air furnaces of the kind now in general use have as standard equipment two openings in the furnace front to receive water heating pipes, and these openings are, according to the standard equipment, spaced approximately two and one-half inches apart on center, and the kind of pipe ordinarily used for such purposes is commonly known as lIlCh pipe, which means that the interior diameter is one inch.

I have found in practice that with ordinary lIOIl pipe of this character it is impractical to make the upper and lower members parallel throughout and then to bend the central-portion on such a small are as to leave the parallel screw threaded ends of the pipe two and one-half inches apart on center.

In order to bend the pipe on a semi-oircle of such diameter that it can be practically and economically accomplished, l have found 1t necessary to form this semi-circular bend at least four or five inches on center. It is, however, desirable in water heaters of this character to have the upper and lower members of the heating unit parallel horizontally, so that water may freely circulate without forming steam pockets, and in order to ac comphsh this double purpose, I have provided at the inner end of the upper member 10 a curved portion 14:, the length of the curve being four or five inches on center, and the direction of the curve being downwardly and laterally, as clearly shown in Figure From the lower end of this curved portion 14, the lower pipe member extends horizontally and forwardly at 16, and then laterally and toward the straight pipe member 13, at the point 17, as shown in Figure 2.

By this construction it is obvious that the semi-circular bend at the inner end of the heating unit may be made on a circle of any desired diameter, which may be conveniently manufactured and yet the ends of the heating unit, which project out through the furnace walls, are arranged one directly above the other and approximately two and onehalf inches apart on center. Furthermore, both the upper and lower members of the heating unit are horizontal, so that water may flow uninterruptedly through them, and without any posibility of forming steam pockets.

Another advantage gained by my improved construction is that, as viewed from above as shown in Figure 2, a considerable portion of the lower heater member is arranged at one side of the corresponding portion of the upper heater member, so that the heat from the fire below will strike directly upon the entire lower heating member, and a considerable portion of the upper heater till member; whereas when the heater element of this character of ordinary construction are used, the lower heater member deflects the heat of the fire from the upper heater member.

I have found that in practice where the ends of a heater member, that project out through the furnace walls, are arranged parallel and two and one-half inches apart on center, and then the curved inner end 'of the heating unit is benton a circle in excess of two and one-half inches on center, with both the upper and lower members parallel throughout, steam will be generated at times and steam pockets formed, which when they escape through the water cause vibrations or poundings of the heating unit, and such structure is objectionable.

The heating elements now in common use are usually formed with two straight pieces of pipe placed two and one-half inches apart on center, and then at the inner end thereof there are two elbows and a short upright pipe section connecting the elbows. This structure is objectionable both on account of its added expense and because of the fact that the elbows must necessarily be of varying thicknesses, as compared with the walls of the pipe proper, so that unequal expansion and contraction occurs and results in breaking and leakage; Whereas with my improved water heater, the walls of the pipe are substantially uniform throughout their entire length and the contraction and expansion is equalized throughout, and there is no opportunity to develop leaks at the joints.

Furthermore, with my improvement, the interior diameter of the heater is uniform throughout, thereby causing a uniform flow of water in all parts of the heater, hence there will be a minimum of solid deposits from the water as compared with heaters which have elbows and the like, which are of greater diameter than the pipe to which they are attached, and hence cause uneven flow of the water and create conditions favorable to the deposits of solids.

lVith my improvement, I have found that the useful life of the heating element is reatly lengthened as compared with the heating units now in common use; that they operate more efficiently so far as the possibility of forming steam pockets is compared; that because they are made on a suitable bending machine, the parallel ends that project through the openings in the furnace are always accurately spaced apart, thus saving the time and labor in applying them to the furnace, as compared with the installation of the ordinary heating elements now in common use; and in addition to all of these advantages, the. cost both of con-.

struction and installation is very greatly reduced.

I claim as my invention:

A water heating element for use in connection with hot air furnaces of the class having two openings for a water'heater arranged in the wall of the furnace in substantially vertical alignment with each other and relatively close together, said water heating element being formed of a single piece of pipe having substantially straight arallel end portions in substantially vertica alignment with each other and designed to project through and beyond said openings in a furnace wall, to connect with water circulating pipes on the exterior of the furnace, said heater being capable of movement inwardly and outwardly through said openings for adjustment of the heater relative to the interior of the furnace or to the water circulating pipes on the exterior of the furnace, the central portion of the pipe being formed into a single approximately circular loop the diameter of which is considerably greater than the distance between the ends of the pipe, and the entire body of the heater element between the end portions thereof being contained within the space between two parallel horizontal planes, one at the top of the upper end of the pipe and the other at the bottom of the lower end of the pipe.

Des Moines, Iowa, December 11, 1926.

GYRUS J. BRISTOL. 

